Merge pull request #136 from cdunn2001/test-both-styled-writers

Test both styled writers

Not only does this now test StyledStreamWriter the same way as StyledWriter, but it also makes the former work more like the latter, indenting separate lines of a comment before a value. Might break some user tests (as `operator<<()` uses `StyledStreamWriter`) but basically a harmless improvement.

All tests pass.